(1) Field of the Invention
The present invention relates to a toner cartridge for use in an image forming apparatus such as a laser beam printer, multifunctional machine or the like, in particular relating to a toner cartridge for storing toner such as a replaceable toner hopper, toner bottle, etc., and an image forming apparatus using this.
(2) Description of the Prior Art
Conventionally, in image forming apparatuses based on electrophotography such as copiers, facsimile machines and the like using a dual-component developer, a toner supply device equipped with a toner cartridge or the like is used to automatically supply toner to the developing device so as to perform continuous printout of images. In such a configuration, if toner runs out, it is possible to supply toner in a simple manner by replacing the toner cartridge, process cartridge or the like.
When toner containers for a toner cartridge, process cartridge or the like are stored in a storage etc., they may be stoked without their position regulated or may be oriented in every possible direction. When, for example, toner cartridges that discharge toner from one side end of the cartridge body, are stacked and positioned vertically with the toner discharge port side down, toner in the cartridge moves down toward the toner discharge port due to gravity with the lapse of time, hence toner near the toner discharge port becomes compact. As a result, toner may aggregate or may become lumps, in the worst cases, blocking the toner discharge port.
If the toner cartridge in this condition is newly mounted, toner is unlikely to be dispensed from the toner cartridge, and it could happen, in the worst case, that it is determined that no toner remains in the toner cartridge even though a plenty amount of toner is left in it.
Particularly, since recent toner is increased in low-temperature fusing performance in order to deal with energy saving, the toner presents low storage stability and shows a tendency to easily cause toner aggregation when the toner cartridge has been left as it is.
Further, in recent image forming apparatuses, because of the demand for miniaturization, toner cartridges as well as developing devices have been downsized, and the mounting space also has become smaller. As a result, each unit is arranged closely to others, so that toner aggregation is liable to occur.
To deal with this situation, when the toner cartridge that has been put in storage is mounted to the image forming apparatus, in some products it is requested for the user etc. to set the toner cartridge after shaking it several times. However, as is often the case, the user tends to forget it, and there occurs the case that the toner will not be discharged. As a result, troubles such as insufficient toner concentration in the developer and/or stoppage of the operation of the image forming apparatus will occur.
Patent document 1 (Japanese Patent Application Laid-open 2000-214667) discloses a developer feeder in which pressure acting on the toner is reduced and excess toner supply is prevented by cutting off part of the conveyor spiral of the conveying auger in the toner cartridge.
However, patent document 1 does not refer to influence on the storage condition of the toner cartridge, hence this configuration still has the drawback or suffers from the aforementioned problem when the toner cartridge has been left behind with its toner discharge port side down under a high-temperature condition for a long time.
Accordingly, there is a demand for a simple mechanism for loosening up toner aggregation when a toner cartridge is set to an image forming apparatus body.